PICANTO(SA) > 2010 > G 1.
0 SOHC > Brake > ABS/ESP(MGH-40) > C1206 Wheel speed
sensor rear-LH open/short
C1206 Wheel speed sensor rear-LH open/short > General Information
Component Location
General Description
The wheel speed sensor is the essential component the ABS ECU uses to calculate vehicle speed and to determine whether wheel
lock occurs.
For example, rear wheel speed signal is used as a referecnce value, for vehicle speed, in front wheel drive vehicles, and if a
difference between front and rear wheel speed occurs, then ABS control is performed.
Wheel speed sensor is active hall-sensor type.
DTC Description
The ABS ECU monitors the wheel speed sensor circuit continuously.
If the sensor signal current is continuously out of the specified range for 140msec, then the HECU determines that the circuit is
open/short, and sets this code.
Warning lamp is turned OFF unless additional faults are detected when the IG KEY is turned ON again, and wheel speed is more
than 10 Km/h .
DTC Detecting Condition
Item Detecting Condition Possible cause
DTC Strategy ● Current Monitoring
● When the sensor signal current is continuously out of the
Enable Conditions
specified range of 4 mA ± 10% ~ 22 mA ± 10% for 140msec.
● Open or short of Wheel speed
1. Only one wheel failure : Inhibit the ABS/VDC control, allow sensor circuit
the EBD control. The ABS/VDC warning lamps are activated, ● Faulty Wheel speed sensor
Fail Safe the EBD warning lamp is not activated.
2. More than two wheels failure : The ABS/EBD/VDC functions
are inhibited. The ABS/EBD/VDC warning lamps are activated.
Specification
Output Voltage Airgap
Sensor Type
HIGH LOW
0.4~1.5mm
Active Type 1.4V 0.7V
Signal Waveform
Fig 1) Normal waveform of wheel speed sensor (Active type)
- High : Approx. 1.4V, Low : Approx. 0.7V
C1206 Wheel speed sensor rear-LH open/short > Scantool Diagnostics > Monitor Scantool Data
Monitor Scantool Data
1. Ignition "ON" & Engine "ON".
2. Connect scantool to Data Link Connector(DLC)
3. Start and drive vehicle in gear and maintain vehicle speed at or above 10km/h. (6.2mph)
4. Monitor the "WHEEL SPEED(RL)" parameter on the Scantool.
1) Specification : Compare with other parameters related to wheel speed sensor.
If it is the same as other parameters, it is in normal condition.
Fig 1) Test Condition : Drive vehicle at a speed of 10km/h or more. (6.2mph or more)
Normal Data
Fig 2) Test Condition : Drive vehicle at a speed of 10km/h or more. (6.2mph or more)
Abnormal Data (Open)
5. Is parameter displayed within specifications?
▶ Fault is intermittent caused by poor connection in wheel speed sensor harness (RL) and/or HECU’s connector or was repaired
and HECU memory was not cleared.
▶ Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
▶ Repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure.
▶ Go to "Terminal and Connector Inspection" procedure.
C1206 Wheel speed sensor rear-LH open/short > Inspection/Repair > W/Harness Inspection
Terminal and Connector Inspection
1. Many malfunctions in the electrical system are caused by poor harness(es) and terminals. Faults can also be caused by
interference from other electrical systems, and mechanical or chemical damage.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3. Has a problem been found?
▶ Repair as necessary and then go to "Verification of Vehicle Repair" procedure.
▶ Go to "Terminal and Connector Inspection" procedure.
Power Supply Circuit Inspection
■ Open or Short Check
1. Ignition "ON"&Engine "OFF".
2. Measure voltage between power terminal of the wheel speed sensor harness connector and chassis ground.
1) Specification : Approx. B+
3. Is the measured value within specifications?
▶ Go to "Signal Circuit Inspection" procedure.
▶ Repair open or short in power circuit between HECU harness connector and wheel speed sensor sensor harness connector
and then go to "Verification of vehicle Repair" procedure.
▶ If there is no problem in Power circuit, Substitute with a known-good HECU and check for proper operation.
▶ If problem is corrected, replace HECU and then go to "Verification of Vehicle Repair" procedure.
Signal Circuit Inspection
■ Wheel speed sensor circuit check
1. Lift the vehicle.
2. Ignition "ON" & Engine "OFF".
3. Turn the wheel by hand.
4. Measure waveform between wheel speed sensor signal terminal of the HECU harness connector and chassis ground with
osciloscope.
1) Specification : High : 1.18~1.68V , Low : 0.59~0.84V
■ Normal waveform
5. Is the measured waveform within specifications?
▶ Substitute with a known-good HECU and check for proper operation.
▶ If problem is corrected, replace HECU and then go to "Verification of Vehicle Repair" procedure.
▶ Repair open or short in signal circuit between HECU harness connector and wheel speed sensor harness connector, and then
go to "Verification of vehicle Repair" procedure.
▶ If there is no problem in signal circuit, go to "Component Inspection" procedure.
C1206 Wheel speed sensor rear-LH open/short > Inspection/Repair > Component Inspection
Component Inspection
■ Wheel speed sensor circuit check
1. Lift the vehicle.
2. Ignition "ON" & Engine "OFF".
3. Turn the wheel by hand.
4. Measure waveform between wheel speed sensor signal terminal of the HECU harness connector and chassis ground with
osciloscope.
1) Specification : High : 1.18~1.68V , Low : 0.59~0.84V
■ Normal waveform
5. Is the measured waveform within specifications?
▶ Fault is intermittent caused by poor connection in wheel speed sensor harness (RL).
▶ Go to "Verification of Vehicle Repair" procedure.
▶ Substitute with a known-good Wheel speed sensor and check for proper operation.
▶ If problem is corrected, replace Wheel speed sensor and then go to "Verification of Vehicle Repair" procedure.
C1206 Wheel speed sensor rear-LH open/short > Verification of Vehicle Repair
Verification of Vehicle Repair
After a repair, it is essential to verify that the fault has been corrected.
1. Connect scantool and select "Diagnostic Trouble Codes(DTCs)" mode
2. Using a scantool, Clear DTC.
3. Operate the vehicle within DTC Detecting Condition in General Information.
4. Using a scantool, Check DTC present.
5. Are any DTCs present ?
▶ Go to the applicable troubleshooting procedure.
▶ System performing to specification at this time.
